There is something about this man's love of sex with birds that strikes me as more messed up than the usual bestiality deviants.
Dogs and horses at least make some vague anatomical sense, but birds are on a whole different level of biological "the pieces won't even fit no matter how hard you try".
Also, while some animal molesters have proven it possible to force an animal to submit to their depraved desires (dogs and horses can both be trained, disturbingly enough, to submit to these perverts), I can't imagine how they would ever get any bird to play along with their sexual desires.